Hydraulic pumps and reversible pump turbines



March 1, 1966 HARTLAND 3,237,565

HYDRAULIC PUMPS AND REVERSIBLE PUMP TURBINES Filed Oct. 7, 1963 5 Sheets-Sheet 1 March 1, 1966 HART-LAND 3,237,565

HYDRAULIC PUMPS AND REVERSIBLE PUMP TURBINES Filed 001;. 7, 1963 5 Sheets-Sheet 2 March 1, 1966 n. HARTLAND HYDRAULIC PUMPS AND REVERSIBLE PUMP TURBINES 5 Sheets-Sheet 5 Filed Oct. '7, 1963 POWER ABSORBED BY PUMP/o March 1, 1966 D. HARTLAND 3,237,555

HYDRAULIC PUMPS AND REVERSIBLE PUMP TURBINES Filed Oct. 7, 1963 5 Sheets-Sheet 4 March 1, 1966 I HARTLAND 3,237,565

HYDRAULIC PUMPS AND REVERSIBLE PUMP 'IURBINES Filed Oct. 7, 1963 5 Sheets-Sheet 5 United States Patent 3,237,565 HYDRAULIC PUMPS AND REVERSIBLE PUMP TURBINES Derek Hartland, Rugby, England, assignor to The English Electric Company Limited, Strand, London, England, a British company Filed Oct. 7, 1963, Ser. No. 314,464 Claims priority, application Great Britain, Oct. 15, 1962, 38,854/ 62 13 Claims. (Cl. 103113) This invention relates to hydraulic pumps and reversible pump turbines.

According to this invention a hydraulic pump or reversible pump turbine includes means for injecting an emulsion of gas and water into the impeller of the pump or reversible pump turbine and for varying the proportions of gas and water so as to vary the density of the emulsion during priming of the pump, or of the reversible pump turbine in operation as a pump.

A number of embodiments of the invention will now be described by way of example with reference to the accompanying drawings, of which:

FIG. 1 shows a general arrangement of hydraulic pump or reversible pump turbine in accordance with the invention;

FIG. 2 is a detailed view of part of FIG. 1;

FIG. 3 is a graph plotting power absorbed against time;

FIG. 4 shows another embodiment of hydraulic pump or reversible pump turbine in accordance with the invention; and

FIG. 5 shows a further embodiment of hydraulic pump or reversible pump turbine in accordance with the invention.

Referring to FIGS. 1 and 2, a large hydraulic pump, i.e. a pump having an input power greater than one megawatt, includes an impeller 11 having a crown 12 and skirt 13 inter-conected by vanes 14. The pump also includes a shaft 15, through which the impeller is driven by a motor 16. The stationary structure of the pump includes a spiral casing 17, which surrounds the impeller and as connected to a delivery pipe 18 incorporating a valve 19. The delivery pipe is connected to a reservoir (not shown) to which water is to be delivered during pump operation.

Immediately below the eye of the impeller 11 is provided a suction tube 20 vertically below and symmetrical with the impeller. At the lower end of the suction tube there is provided an inlet bend tube 21 which communicates through a passage 22 with a lower reservoir (not shown) from which water is to be pumped.

The passage 23 surrounding the impeller may be provided with adjustable guide vanes 24 and a ring of fixed vanes 25 as shown, through which water is delivered by the impeller 11 into the spiral casing 17, or alternatively only a ring of fixed diffuser vanes may be provided. I

As shown in FIG. 2, the centre of the crown 12 is formed with a cavity 26 connected by a bore 27 with an annular space 28 between the stationary structure and the rotating par-ts of the pump, sealing rings 29, 30 between the stationary structure and the rotating parts being provided at the top and bottom of the space 28. The space may either be vented to atmosphere (or, where thae suction tube is at sub-atmospheric pressure, to a vacuum chamber) through a bore 31 and valve 32, or may be connected to a source of compressed air, or alternatively may be closed off.

A labyrinth seal 33 is provided between the crown 12 and the stationary structure, and a further labyrinth seal 34 is provided between the skirt 13 and the stationary structure at the top of the suction tube 20. A drain pipe 35 is provided between the sealing ring 30 and the labyrinth seal 33 through which any leakage is drained off.

A pipe 40 is conected to a source of water under pressure, for example to the delivery pipe 18 as shown. In pumps having adjustable guide vanes 24, these may be closed and the valve 19 may be open, allowing water under pressure into the spiral casing 17. In this case the pipe 40 may optionally be connected to the spiral casing 17 The pipe 40 contains a valve 41, by which the flow of water may be controlled, and leads to an emulsifier 42. Compressed air is fed to the emulsifier 42 through a valve-controlled supply pipe 43 from any convenient source; the emulsifier may be of any known or convenient type, for example one in which the air and water are converted into an emulsion by mechanical means, or of the hydraulically-energised type.

The emulsion passes to a port or ports 44 in the suction tube 20, the pipe 40a curving upwards towards the port or ports 44 so that the emulsion is directed into the impeller 11. A branch pipe 45 and valve 46 are provided, to enable the pipe 40a to be drained.

An emulsifying agent, such as a detergent, may be supplied to the emulsifier 42, for example through pipe 47.

In starting operation of a pump or of a reversible pump turbine in the pumping sense, the impeller 11 is first accelerated by any known or convenient means such as an auxiliary motor from rest to synchronous speed in air, the water being depressed down the suction tube by the introduction of compressed air through pipe 31. A small amount of water may be admitted to the impeller seals during this phase, to reduce the risk of the fine clearances, with which the impeller runs, being taken up and seizing occurring.

Then at synchronous speed the motor 16 is connected to the power supply, e.g. to the grid, and synchronised and the auxiliary motor may be disconnected.

The power absorbed in these two phases rises from zero 'to about 3 percent of the normal full load, and they may be completed, for example, in two minutes (see FIG. 3).

In FIG. 3 the full line represents the starting of a pump fitted with adjustable guide vanes 24, which are closed during this period, and the dotted line represents the star-ting of a pump having only the fixed diffuser vanes 25.

Next the impeller is progressively filled with water; owing to the centrifugal effect the water builds up progressively from the outer periphery of the impeller inwards. The filling may be achieved either (a) by gradually exhausting the air from the suction tube through pipe 31 allowing the water level to rise slowly into the impeller inlet. The water picked up by the vanes 14 is centrifuged to the outer periphery and displaces the air in the impeller radially inward; the air is thus compressed and opposes the rise of the water level, and thus the process is stable. Or it may be achieved by (b) feeding water from the delivery pipe 18 into the space between the impeller 11 and the adjustable guide vanes 24 (or fixed diffuser vanes 25) and thence inward into the impeller against the action of centrifugal force. The water may be fed in through a pipe connected to the wall of passage 23, or connected to the stationary casing adjacent the crown 12 (outside seal 33) or adjacent the skirt 13 of the impeller. Or again it may be achieved by (c) directing a jet or jets of water aimed at the impeller inlet from the suction tube, the jets being supplied from the delivery pipe 18, or from an extraneous source, e.g. through pipes 40, 40a.

The inner boundary of the water may be brought inward in this way to substantially the radius of the smallestdiameter part of the skirt 13, and it is found that the power absorbed in this phase rises from 3 percent to about percent of the normal full load in a machine fitted with adjustable guide vanes, which are in the closed position. This third phase may take a further minute.

The three phases described above are reversible, i.e. the sequence can easily be reversed at any time, and controllable, i.e. the rate of increase of power absorption can be controlled.

At the end of the third phase air will be circulated in the suction tube by the exposed parts of the impeller vanes 14, and in accordance with the invention the density of the circulating medium is progressively changed, so that load may be taken by the pump motor 16 at a con trolled rate, in the following manner: an emulsion is injected into the impeller through pipe 40a, first at a low density, i.e. with a high ratio of air to water. The density is then gradually increased, preferably by reducing the air supply and maintaining constant the rate of water supply, until the greater part of the impeller 11 and the top of the suction tube 20 is substantially filled with water; the air injected is exhausted to atmosphere in a controlled manner through pipe 31.

The power absorbed rises from about 10 percent of normal full load to about 27 percent when the impeller is completely filled with water in the case of pumps with adjustable guide vanes, and to about 60 percent in the case of pumps with fixed diffuser vanes. Hitherto this rise took place in a fraction of a second; by use of the invention the rise in power is caused to take place over a longer period, at a rate at which the electrical grid can more easily accept the load.

For example this rise in power may take more than 20 seconds, as shown in chain-dashed lines in FIG. 3.

Finally, in the fifth phase, the adjustable guide vanes 24 (or in pumps with only fixed guide vanes 25, the delivery valve 19) are gradually opened so that the power absorbed is increased in a controllable manner from 27 percent or 60 percent respectively to full load.

The supplies of air and water through pipe 40a are shut off in normal operataion.

In an alternative, after the motor 16 is synchronised, the impeller may be filled entirely by means of the injection of emulsion, and the third phase (filling the outer periphery of the impeller) as described above is therefore omitted.

Referring now to FIG. 4, there is shown a modification of the arrangement of FIGS. 1 and 2 in which water is supplied from the delivery pipe 18 through pipe 70, controlled by valve 71, to a venturi 72. Compressed air is fed through pipe 73 to the throat of the venturi or to a distribution manifold at the throat of the venturi, and the emulsion of air and water thus produced is injected into the impeller through port 74. A drain pipe 75 and valve 76 are provided, and an emulsifying agent, such as Teepol or By-Prox (registered trademarks), may be supplied to the throat of the venturi through a pipe 77.

Referring to FIG. 5, a further modification of the arrangement of FIGS. 1 and 2 is shown, in which instead of the pipe 43 being connected to an external source of compressed air, it is supplied with air exhausted from the impeller space through pipe 31. A two-way valve 47 is provided to enable the pipe 31 alternatively to be vented to atmosphere or connected to pipe 43.

-It will be apparent that various combinations are possible within the scope of the invention; for example the air supply pipe 73 (FIG. 4) of the venturi 72 may be connected to be supplied with air exhausted from the impeller space through pipe 31.

, What I claim as my invention and desire to secure by Letters Patent is;

1. A hydraulic machine,.comprising a casing an impeller mounted for rotation in said casing,

a suction tube mounted on said casing upstream of said impeller for connection to a liquid reservoir,

a delivery tube mounted on said casing downstream of said impeller,

control means mounted on said casing for causing said liquid to flow along the suction tube towards said impeller at a controlle rate,

an emulsifier connected to a source of both gas and liquid for generating an emulsion therefrom,

means for injecting said emulsion into said suction tube adjacent said impeller during the controlled flow of said liquid thereto, and

means for varying the proportions of gas and liquid in said emulsifier during the injection of said emul- 2. A hydraulic machine according to claim 1, wherein said control means comprises a valve selectively operable to introduce a gas into said impeller, and

means for exhausting said gas from said impeller whereby to permit said liquid to flow along the suction tube towards said impeller.

3. A hydraulic machine according to claim 2, wherein said emulsifier comprises,

a venturi tube having an inlet, a throat and an outlet,

and

a first pipe connectingsaid inlet to a liquid pressure source,

a second pipe connecting saidthroat to a gas pressure source, and

a third pipe connecting said outlet to said suction tube.

4. A hydraulic machine according to claim 3, wherein said gas pressure source is the said gas exhausted from said impeller as the said liquid flows along the suction tube.

5. A hydraulic machine according to claim 3, wherein said emulsifier further comprises a fourth pipe connecting said throat to a source of an emulsifying agent.

6. A hydraulic machine comprising,

a casing,

an impeller mounted for rotation in said casing,

a suction tube communication with a liquid reservoir and connected to said casing upstream of the impeller,

a spirally-wound delivery tube connected to said casing downstream of said impeller,

valve means mounted on said casing and movable between a first position for introducing gas into said impeller and a second position for exhausting said gas therefrom whereby to cause said liquid to flow along the suction tube towards said impeller at a controlled rate,

an emulsifier connected both to a source of gas, and a source of liquid, for generating an emulsion therefrom,

means for injecting said emulsion into said suction tube towards said impeller during the controlled flow of said liquid thereto, and

means for varying the proportions of gas and liquid in said emulsifier during the injection of said emulsion.

7. A hydraulic machine according to claim 6, comprising means for supplying an emulsifying agent to said emulsifier.

8. A hydraulic machine according to claim 7, wherein said emulsifier comprises,

a venturi having an inlet and a throat, and

means for supplying liquid to said inlet and for supplying gas to said throat to generate said emulsion.

9. A hydraulic machine according to claim 6, wherein said emulsion is generated in said emulsifier by mechanical means.

10. A hydraulic machine comprising a casing,

an impeller having a leading edge and a trailing edge,

means mounting said impeller for rotation in said casing,

a first tube mounted on said casing and communicating at one end with the leading edge of said impeller and at the other end with a water supply,

a second tube mounted on said casing and communicating with the trailing edge of said impeller,

a control valve mounted on said casing and selectively operable to permit water to advance along said first tube towards said impeller at a controlled rate,

an emulsifier connected to a source of air and a source of water for generating an aerated emulsion from said water,

a conduit connected between said emulsifier and said first tube for directing said aerated emulsion towards said impeller during the controlled flow of water thereto, and

means for varying the proportions of water and air supplied to said emulsifier from said sources.

11. A hydraulic machine according to claim 10, where- References Cited by the Examiner UNITED STATES PATENTS 1,504,776 8/1924 Nagler 103-113 1,737,870 12/1929 Telfer 103113 1,739,600 12/1929 Loth 103l13 2,795,873 6/1957 Hoflman 1O3113 3,047,267 7/1962 Peyrin 253-1 17 OTHER REFERENCES German Printed Application No. 1,041,202.

SAMUEL LEVINE, Primary Examiner.

HENRY F. RADUAZO, Examiner. 

1. A HYDRAULIC MACHINE, COMPRISING A CASING AN IMPELLER MOUNTED FOR ROTATION IN SAID CASING, A SUCTION TUBE MOUNTED ON SAID CASING UPSTREAM OF SIAD IMPELLER FOR CONNECTION TO A LIQUID RESERVOIR, A DELIVERY TUBE MOUNTED ON SAID CASING DOWNSTREAM OF SAID IMPELLER, CONTROL MEANS MOUNTED ON SAID CASING FOR CAUSING SAID LIQUID TO FLOW ALONG THE SUCTION TUBE TOWARDS SAID IMPELLER AT A CONTROLLE RATE, AN EMULSIFIER CONNECTED TO A SOURCE OF BOTH GAS AND LIQUID FOR GENERATING AN EMULSION THEREFROM, MEANS FOR INJECTING SAID EMULSION INTO SAID SUCTION TUBE ADJACENT SAID IMPELLER DURING THE CONTROLLED FLOW OF SAID LIQUID THERETO, AND MEANS FOR VARYING THE PROPORTIONS OF GAS AND LIQUID IN SAID EMULSIFIER DURING THE INJECTION OF SAID EMULSION. 